knock out

verb

1. To strike or render unconscious

   “I accidentally knocked out the glass in my picture frame.”

2. To strike or render unconscious

   “The boxer knocked out his opponent in the third round.”

   “In the autumn there was a row at some cement works about the unskilled labour men. A union had just been started for them and all but a few joined. One of these blacklegs was laid for by a picket and knocked out of time.”

3. To strike or render unconscious

   “The allergy pill knocked him out for a good three hours.”

4. To strike or render unconscious

   “That's a put-you-straight-to-sleep book if there ever was one, and I knocked right out after two paragraphs.”

5. To strike or render unconscious

   “Running errands all day really knocked him out.”

6. To strike or render unconscious
7. To strike or render unconscious
8. To strike or render unconscious

   “The antitank gun knocked out the enemy tank.”

9. To strike or render unconscious

   “As they were approaching bankruptcy from being knocked out of the calculator market, they began development on the first commercially available microcomputer, the Altair.”

   “Tottenham were knocked out of the Europa League, despite a comfortable victory over Shamrock Rovers in Dublin.”

10. To communicate (a message) by knocking.

    “The prisoner knocked out a message on the wall for the prisoner in the adjoining cell.”

11. To complete, especially in haste; knock off.

    “They knocked out the entire project in one night.”

12. To lose the scent of hounds in fox-hunting.
13. To leave college after hours—after half-past ten at night when the doors have been locked.

    “"Hullo!" he said, getting up; "time for me to knock out, or old Copas will be in bed. […]"”

14. To obtain or earn (something, often money or food).
15. To sell.